[dao-]

In about:config, try looking for browser.tabs.dragDrop. The createGroup... and moveOverThresholdPercent flags control the group creation behavior during drag and drop. If anyone finds values that make it less likely to accidentally create groups while still allowing intentional grouping via drag and drop, I can channel these back to the team.

[internet_points]

I'm guessing your telemetry will tell you a lot of users have started using tab groups. They may have done so by mistake. My tabs each take up like half an inch of the screen and I don't have a gaming mouse; I now have multiple tab groups which I never intended making. As this is a quite technical feature, maybe dragging should be off by default, or only when e.g. holding shift and dragging or something?

(Yes it's a beautiful feature and probably lots of people want it, just noting that the dragging is confusing. I can't think of a good way to solve the problem that doesn't make it slightly more difficult/nerdy to use.)

[guerby]

Is there a way to disable the creation of tab group by drag and drop altogether by tweaking these parameters ?

Also I noticed another thing: drag and droping a tab on a folded tab group doesn't work. You have to unfold the tab group then you can drag and drop a tab into it.

It would be great to allow drag and drop of a tab on a folded tab group and if dropped just put the tab at the end of the group, it would make the tab group feature more useful by allowing to quickly select and drop tabs where they should go.

[dao-]

You could just set `browser.tabs.dragDrop.createGroup.delayMS` to a high value like 3000; that would mean having to rest the mouse for three seconds to group tabs during drag and drop.